The invention relates generally to network engineering. More specifically, the invention relates to systems and methods that configure high-speed data links between dispersed locations to reroute data traffic between Backbone Routers (BRs).
BRs are routers designed to operate in the Internet backbone or core. A BR supports multiple telecommunications interfaces of the highest speed in use in the core Internet and forwards Internet Protocol (IP) packets at full speed over all of them. BRs also support the routing protocols being used in the core.
A BR is distinct from a Provider Edge (PE) router, also known as an Access Router (AR), since ARs are located at the edge of a backbone network and connect to BRs. ARs contain interfaces that connect to multiple customers and provide a diverse set of IP services such as Virtual Private Networks (VPNs), multicast, and other protocols implemented in customer private network domains and Local Area Networks (LANs). A BR is usually deployed to lower network costs by aggregating traffic into higher rate interfaces, achieving statistical multiplexing and transporting data more economically across longer distances.
Routers operate in two different planes, the control plane, in which the router learns the outgoing interface that is most appropriate for forwarding specific packets to specific destinations, and the data plane, which is responsible for the actual process of sending a packet received on a logical interface to an outbound logical interface.
FIG. 1 shows a typical long-distance network architecture. Redundancy is achieved by connecting each AR (circles) to two BRs (squares) at the same Central Office (CO) location. More specifically, one or more AR interface ports are connected to one or more interface ports of a first BR and one or more interface ports of the same AR are connected to one or more interface ports of a second BR. The connection between interface ports is usually by optical fiber and can traverse other equipment, such as automatic or manual Fiber cross-Connect (FXC) devices or other optical transport equipment.
The physical connection between an AR and a BR is called an “AR-BR link”. This AR-BR link includes the interface ports on the two routers. Links that completely lie within the same CO are called “intra-office” links. Links that span two or more COs are called “inter-office” links. If AR-BR links between both BRs are operational (or active), traffic from an AR can flow to either of the two BRs depending on the data traffic's eventual destination. If one or more links between an AR and BR go down (become non-operational), then AR traffic flows to the functioning BR or BRs over the remaining operational links. An AR-BR link on an operational AR becomes non-operational if the following components either fail, or are taken out of service by operations personnel or systems: one or more ports on both ends of an AR-BR link, the connection between the ports of the AR-BR link, or a BR in part or in whole. Note that although the sequence of events might differ in time, whether these components fail or are taken out of service has the same effect on eventual traffic flow.
FIG. 1 also shows ARs that are not co-located with the BRs and are called “remote” ARs (diamonds). In this configuration, the remote ARs also connect to two BRs. Often, the remote ARs connect to BRs in different locations. The purpose is to restore against a failure of the inter-office AR-BR link, which must be transported by long-distance optical transmission equipment and may be more susceptible to failure than intra-office links. While not shown in FIG. 1, inter-office links also connect pairs of BRs.
There are two disadvantages to the standard architecture:    1) at a location having a large number of ARs, the required numbers of ports on a BR may exceed equipment capabilities, and    2) all of the links between an AR and its first BR need to have sufficient capacity to support all traffic from the same AR and its second BR if the second BR fails and vice-versa.
The challenge for network operators is to maintain traffic throughput under the most probable failure conditions. A system and method that responds to failures or maintenance of BRs and their intra-office AR-BR links and then dynamically configures high-speed data links between ARs and BRs at geographically dispersed locations and reroutes traffic to those links achieves the above goal in a cost-efficient manner.